Supplying Garden Water Needs with Rainwater Harvesting Tanks

Rising temperatures and inconsistent rainfall introduce gardening challenges for homeowners, so more turn to rainwater harvesting tanks to independently supply their landscape irrigation needs. By collecting and storing rain from storms in purpose-built containers, households can conserve municipal water access and hedge against drought conditions hampering gardens. But what size rain harvesting system best fits the typical home garden?

Calculating Garden Water Requirements

A typical 150m2 family garden requires around 1500 litres weekly for sufficient irrigation during the growing season. Factoring in storage to carry through prolonged dry periods without rain, a 2,500 - 5,000 litre rainwater harvesting tank offers an appropriate capacity range. As a rule of thumb, every 2-3 mm of rain falling onto 1 m2 of catchment area equals 1 litre of harvestable water.

Maximising Catchment Area

Maximise the catchment area by connecting PVC drainage pipes along the entire span of available roof lengths to recharge tanks even during short bursts regularly. Using multipipe supplies inflow from the front and rear elevations into one tank or daisy-chain tanks together. Large 5,000-liter tanks generally need at least 40m2 roof collection space for climate consistency.

Essential Rain Harvesting Components

Critical components for garden water rain harvesting include:

  • An appropriately sized storage tank supported by a concrete base or on the wall of the house

  • A debris filtering system preventing contaminant and sediment inflow

  • Seamless gutters with drainage routing all roof runoff into the tank

  • An integrated electric irrigation use pump connecting to garden beds/hoses

  • An overflow outlet

  • Water level gauge for visibility into current storage volume

With the proper foundation of catchment ventilation, storage capacity, filtration and distribution hardware in place, households gain affordable resilience against watering disruptions. Inspecting and maintaining rain harvesting equipment regularly ensures a smoothly functioning system sustaining gardens for years. Leveraging free ambient precipitation reduces monthly bills!